Conventionally, bags for containing an article, which are bag bodies where necessary places of resin sheets having flexibility are adhered together with a heat seal or the like to form an article containing portion enclosed by the sheets, have been widely used. Among these, there are bags for containing an article including a gusset at a bottom portion thereof.
Bags for containing an article including a gusset are bags where, at the bottom portion of a bag body configured from a flat front sheet and a flat rear sheet, a bottom sheet that is continuous with the aforementioned sheets or is a sheet that is different from the aforementioned sheets is disposed.
The bottom sheet is, for example, folded in two at the inner side of the bag body—i.e., at the article containing portion side—so that the cross-sectional shape of the bag for containing an article at the bottom portion is formed in a “Σ” shape by the front sheet, the rear sheet and the bottom sheet. By disposing the bottom sheet folded in this manner, the bag for containing an article is such that it has a flat form in a state where an article is not disposed in the article containing portion, and the bottom sheet is expanded and the internal volume of the bag for containing an article can be increased when an article is contained in the article containing portion.
However, when the bag for containing an article is swung or suddenly lifted up in a state where an article is disposed in the article containing portion, there have been cases where a force exceeding the strength of the sheets is suddenly concentrated, due to the weight of the article, at places of contact points where the front sheet, the rear sheet and the bottom sheet are respectively adhered together, whereby the bottom sheet ends up being torn.
In a case where the bag for containing an article is used as a deaerated bag that can be stored compact by compressing an article whose volume is large because it includes air, such as bedding or clothing, by deaerating air present in the article containing portion, the fact that tears of the bottom sheet in this manner have been a fatal problem because the bag for containing an article no longer fulfills the function of maintaining the deaerated state of the article containing portion.